Braking device

ABSTRACT

A brake system for a wheeled walker frame having two walker frame legs with two telescopically adjustable frame tubes, of which one frame tube supports in its upper region a handle and a brake lever and the other is provided in its lower region with a brake device for braking a wheel. A telescopically adjustable brake rod is disposed within the frame tubes, between the brake lever and the brake device, and includes two parallel rods of which one is interconnected with the brake lever and the other is interconnected with the brake device. An axial longitudinal adjustment of the frame tubes to the desired vertical position synchronously causes a corresponding alteration of the length of the brake rod. At least one device is provided for locking the frame tubes and the parallel rods.

FIELD OF THE INVENTION

The present invention relates to a brake system for a wheeled walker.

BACKGROUND OF THE INVENTION

Wheeled walker frames are normally constructed from metal tubing, whichresults in constructions which are stable, durable and relatively light.According to the legislation of most European countries, such a wheeledwalker frame must satisfy certain requirements in order to be employedwithin public medical care. It should have as hygienic an exterior aspossible, ie. clean, smooth surfaces, few dirt pockets and fewprojecting parts. It should further be provided with a brake for eachhandle which in turn must be capable of being adjusted in the verticaldirection in as simple a manner as possible, in which event theadjustment of the brake should preferably take place synchronously, oremploying very simple measures. A glance at prior art constructionsshows that the transmission of the braking force from the handle to thebrake substantially takes place via three principles: a) a flexiblecable, b) a strap or lanyard of textile, or c) a metal rod, all disposedwholly or partly outside the metal tubing. These prior art brake systemssuffer from drawbacks. The flexible cable forms loops which may catch inprojecting objects such as handles on furniture. The same applies to thetextile strap which must be adjusted after a movement of the handle, andalso the metal rod located outside the tubing can catch in extraneousobjects. For all three types, it is a common feature that they areunattractive and difficult to keep clean, which is of importance sincewheeled walker frames are lent out to different patients during a periodof convalescence, and therefore must be carefully cleaned before beingpassed on to the next user.

SUMMARY OF THE INVENTION

The object forming the basis of the present invention is to obviate orat least reduce the above outlined drawbacks inherent in prior artwheeled walker frames.

This object is solved according to the present invention.

The present invention makes possible the enclosure of the brake systemin the frame tubing, which eliminates the drawbacks inherent in priorart wheeled walker frames with projecting parts and brake cables, etc.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will be described in greater detailhereinbelow, with reference to the accompanying drawings, in which:

FIG. 1 shows a section through one leg of a wheeled walker frame whichhas two telescopic tubes with lockable and extensible brake rods.

FIG. 2a shows a section through a part of one leg of a wheeled walkerframe with a slightly deviating form of brake rod and locking device.

FIG. 2b shows a cross section through the leg of the wheeled walkerframe with the parts in the displacement position.

FIG. 2c shows a similar cross section to FIG. 2b, with the parts in thelocked position.

FIG. 3a shows a longitudinal section through parts of a thirdembodiment, with the parts in the displacement position.

FIG. 3b shows a similar cross section to FIG. 3a with the parts in thelocked position.

FIG. 4a shows a section through one leg of a wheeled walker frameaccording to yet a further embodiment, the brake rod being of thedrawing action type.

FIG. 4b shows a section through a part of one leg of a wheeled walkerframe with the parts in the locked position.

FIG. 4c shows a cross section through the parts of FIG. 4b.

DETAILED DESCRIPTION

With reference to FIG. 1, an outer frame tube 10 constitutes, togetherwith an inner frame tube 11, carrying elements for a handle 12 and abrake lever pivotal about a shaft 15, the handle being shown in threedifferent positions, a braking position 13, a neutral position 13 a anda locked position 13 b. The brake lever is provided with a pressuresurface 14 for contact with a spring-biased pressure plate 16 which isapplied on the upper end of a rod 17 a which constitutes the onecomponent of an extensible brake rod 17. The other component is a tube17 b in which the rod 17 a runs and in whose lower end a brake device 18in the form of a threaded pin is screwed in, the pin, on braking, beingurged into abutment against a walker frame wheel 19 (partly shown on theDrawing). Since it should be possible to adapt a wheeled walker frame toboth tall and short people, the handle must be capable of being raisedor lowered and, after adjustment, be securely fixed in either position.To this end, there is provided, at the upper region of the outer frametube 10, an interiorly threaded aperture 110, for example a sleeve nutin which a screw 111, provided with a thumb wheel, may be twisted in andout. In the inner position, both of the telescopic frame tubes aremutually locked, since the screw has penetrated into one of the holes112 which are stepwise punched out in the inner frame tube 11.

A similar locking arrangement with sleeve nut 113 and screw 114 ismounted at the tube 17 b. When the screw 114 is threaded in, the rod 17a is clamped fast against the tube 17 b. The screw passes through anoval hole 115 punched in the outer frame tube 10. The length of the holeis slightly greater than the diameter of the screw 114, in order for thebrake rod 17 in the locked position to be able to be pressed downwardfar enough for the brake device 18 to have a braking effect against thewalker frame wheel 19.

When the vertical position of the handle is altered, the procedure is asfollows. Both of the screws 111 and 114 are backed off and threaded outso far that the telescopic units,i.e. the rods 17 a and 17 b, as well asthe frame tubes 10 and 11 are free and thereby mutually displaceable.The handle is raised or lowered until a suitable hole 112 in the frametube 11 is in register with the screw 111, which is then tightened intothe hole 112, thereby fixing the frame tubes to one another. Thereafterthe screw 114 is tightened, so that the rod 17 a is locked against thetube 17 b.

FIGS. 2a, b, c illustrate a slightly different version of the presentinvention. Here, the telescopic frame tubes are designated 20 and 21.The mutual fixing in the vertical direction of these elements is thesame as in the embodiment according to FIG. 1, i.e. a screw 211 runs ina sleeve nut 210. The screw 211 is provided with a Stub shaft 216 which,on vertical fixing, passes through a hole 212 in the inner frame tube21. The brake rod 217 is, in this embodiment, composed of two rods 217 aand 217 b of square profile. The rods are axially displaceable inrelation to one another and are locked at predetermined distances inthat the rod 217 a (in FIG. 2a the left-hand rod) is provided with a pin214. In the right-hand rod 217 b, there are provided slots 215 at thesame distance and the same spacing as the holes 212 in the inner frametube 21. With the aid of the screw 211, the stub shaft 216 is forcedagainst the rod 217 a which is, in such instance, displaced against therod 217 b and the pin 214 engages in the slot 215. The rods are therebyaxially fixed. A U-bent plate 213 ensures the lateral positioning of therods. The locking of the adjustable parts thus takes place synchronouslywith the aid of the screw 211 provided with the thumb wheel, the stubshaft 216 and the pin 214.

The procedure on adjustment of the vertical position of the handle issimple. The screw 211 is backed off as far as shown in FIG. 2b, i.e.completely out of the hole 212. Then, the pin 214 has, under the actionof a spring 218, released its engagement with the slot 215 and the rods217 a and 217 b are axially displaceable in relation to one another. Theheight of the handle can therefore be adjusted and, by screwing in thescrew 211, the frame tubes are locked at the same time as the pin 214enters into engagement with the slot 215. The length and design of thestub shaft 216 are such that a certain radial play exists between thebrake rod and the frame tube, in order for the brake rod to be displacedwithout excessive friction and without jeopardizing the braking functionwhich, after all, presupposes a few millimetres'vertical movement.

In the two described embodiments, the vertical positions of the handlewere limited to a predetermined number. In the embodiment describedbelow in connection with FIGS. 3a and 3 b, this adjustment is stepless.

The inner frame tube 31 is provided with a longitudinal slot 312 whichis slightly longer than the total extent of the vertical adjustment. Inthe outer frame tube 30, there is a hole 315 of the same diameter as thewidth of the slot 312. The locking of the two frame tubes takes place byclamping between a nut 318 located within the inner frame tube, and ahead disposed on the screw 311, the periphery 320 of the head beingtoothed and constituting a grip for a thumb wheel or knob 319 which isrotatable about a shaft 316 journalled in a hole in the screw 311. Thefree end of the shaft 316 is designed as a cross bit with whose help anarrest screw 321 can be rotated in a thread disposed in the tube 317 bof the brake rod 317. Since this, for reasons of weight, should be asthin-walled as possible, a socket 322 is disposed around the end of thetube and the thread is disposed for the greater part in this socket.Also in this embodiment, the locking of the adjustable parts takes placesynchronously with the aid of the screw 311, the shaft 316 and thearrest screw 321.

The locking mechanism functions as follows. Starting from the lockedposition according to FIG. 3a, the arrest screw 321 is first backed offso that the parts of the brake rod are released. Thereafter, the knob319 is drawn outwards until it comes into engagement with the toothing320 of the screw 311. The screw can then be released and the clampingpressure ceases and the handle may be placed in the desired verticalposition. The locking takes place most simply in the reverse sequence.First, the frame tubes are clamped together, the knob 319 is pressed inand the arrest screw is tightened so hard that the elements of the brakerod are locked in the axial direction.

The embodiments of the present invention described in the foregoing havea compression brake rod, to which the present invention is notrestricted. The brake rod may also operate by a drawing action. Such avariation is illustrated in FIGS. 4a-4 c.

The brake lever,.which in the previously described examples, had acompression action on the brake rod must, in the present embodiment, actin the drawing direction instead. Thus, the brake lever 43 (see FIG. 4a)acts against a compression surface 46, located above its pivot axis 45,on an ear 49 which is connected to a rail 47 a which in turn, togetherwith a similar rail 47 b, forms the brake rod 47.

The rails run in one another and can be mutually locked axially via apin 416 disposed in the rail 47 b and which engages in recesses 415 inthe other rail 47 a. This engagement may take place when the rails arepressed together radially. The mechanism for this locking operation issimilar to that illustrated in FIG. 2. A screw 411, provided with aknob, is rotatable in a thread in a sleeve nut 410 fixedly welded to theouter frame tube 40. Roughly halfway backed-off, the screw releases thecontact with the inner frame tube 41. The rails of the brake rod arethen held apart under the action of a thin leaf spring 418. The handle412 may thus now be raised or lowered to the desired level. When thescrew 411 is located in register with a hole in the inner frame tube,the screw is threaded in so far that the pin 416 is in engagement with arecess 415. The length of the screw is adapted such that no radial“clamping pressure” occurs, but that a certain play exists when thescrew is fully tightened. As a result, the brake rod is not impeded byfriction in its movement, either between the screw and the rail orbetween the rail and the inner frame tube on braking.

Since the braking operation takes place by a drawing action, the brakedevice 420 is of a different concept than the previously describedvariations. The drawing force from the brake rod is transmitted via adrawing linkage 422 and a rocker arm 421 as compression force to thebrake device. The advantage in a drawing action brake rod is that it maybe permitted to be considerably more lightweight in dimensions than acompression action brake rod, since there is no risk of outward bendingin a drawing action brake rod. Thus it is conceivable to manufacture therails 47 a and 47 b of plastic.

What is claimed is:
 1. A wheeled walker comprising first and secondwalker frame legs, each leg including: an upper frame tube having anupper end; a lower frame tube having a lower end, the lower frame tubeengaging the upper frame tube while permitting telescopic longitudinalmovement therebetween; a handle on the upper frame tube upper end; awheel rotatably mounted on the lower frame tube lower end; a brake leverconnected to the upper frame tube upper end adjacent the handle andnormally assuming a non-braking position while being pivotable to abraking position; a brake device connected to the lower frame tube lowerend and adapted to engage and brake the wheel; a brake rod extendingwithin the upper frame tube and the lower frame tube and including anupper rod member and a lower rod member engaging the upper rod memberwhile permitting telescopic longitudinal movement therebetween, theupper rod member having an upper end connected with the brake lever, thelower rod member having a lower end connected with the brake device; andlocking means extending into the upper frame tube and the lower frametube to engage the brake rod, said locking means being adapted formovement between an unlocking position, permitting longitudinal movementbetween the upper frame tube and the lower frame tube and longitudinalmovement between the upper rod member and the lower rod member, and alocking position, prohibiting longitudinal movement between the upperframe tube and the lower frame tube and longitudinal movement betweenthe upper rod member and the lower rod member such that pivoting of thebrake lever from the non-braking position to the braking position movesthe brake rod longitudinally within the upper and lower frame tubes,causing the brake device to engage the wheel.
 2. A wheeled walker asclaimed in claim 1, wherein the locking means is adapted to lock theupper and lower frame tubes and the upper and lower rod memberssynchronously.
 3. A wheeled walker as claimed in claim 2, whereinpivoting of the brake lever from the non-braking position to the brakingposition moves the brake rod downwardly within the upper and lower frametubes, bringing the brake device into engagement with the wheel.
 4. Awheeled walker as claimed in claim 2, wherein: pivoting of the brakelever from the non-braking position to the braking position moves thebrake rod upwardly within the upper and lower frame tubes; and the brakedevice includes a drawing linkage and a rocker arm which are responsiveto upward movement of the brake rod to bring the brake device intoengagement with the wheel.
 5. A wheeled walker as claimed in claim 1,wherein pivoting of the brake lever from the non-braking position to thebraking position moves the brake rod downwardly within the upper andlower frame tubes, bringing the brake device into engagement with thewheel.
 6. A wheeled walker as claimed in claim 1, wherein: pivoting ofthe brake lever from the non-braking position to the braking positionmoves the brake rod upwardly within the upper and lower frame tubes; andthe brake device includes a drawing linkage and a rocker arm which areresponsive to upward movement of the brake rod to bring the brake deviceinto engagement with the wheel.
 7. A wheeled walker comprising first andsecond walker frame legs, each leg including: an upper frame tube havingan upper end; a lower frame tube having a lower end, the lower frametube engaging the upper frame tube while permitting telescopiclongitudinal movement therebetween; a handle on the upper frame tubeupper end; a wheel rotatably mounted on the lower frame tube lower end;a brake lever connected to the upper frame tube upper end adjacent thehandle and normally assuming a non-braking position while beingpivotable to a braking position; a brake device connected to the lowerframe tube lower end and adapted to engage and brake the wheel; a brakerod extending within the upper frame tube and the lower frame tube andincluding an upper rod member and a lower rod member engaging the upperrod member while permitting telescopic longitudinal movementtherebetween, the upper rod member having an upper end connected withthe brake lever, the lower rod member having a lower end connected withthe brake device; and a single locking device adapted for movementbetween an unlocking position, permitting longitudinal movement betweenthe upper frame tube and the lower frame tube and longitudinal movementbetween the upper rod member and the lower rod member, and a lockingposition, prohibiting longitudinal movement between the upper frame tubeand the lower frame tube and longitudinal movement between the upper rodmember and the lower rod member such that pivoting of the brake leverfrom the non-braking position to the braking position moves the brakerod longitudinally within the upper and lower frame tubes, causing thebrake device to engage the wheel.
 8. A wheeled walker as claimed inclaim 7, wherein the single locking device is adapted to lock the upperand lower frame tubes and the upper and lower rod members synchronously.9. A wheeled walker as claimed in claim 8, wherein pivoting of the brakelever from the non-braking position to the braking position moves thebrake rod downwardly within the upper and lower frame tubes, bringingthe brake device into engagement with the wheel.
 10. A wheeled walker asclaimed in claim 8, wherein: pivoting of the brake lever from thenon-braking position to the braking position moves the brake rodupwardly within the upper and lower frame tubes; and the brake deviceincludes a drawing linkage and a rocker arm which are responsive toupward movement of the brake rod to bring the brake device intoengagement with the wheel.
 11. A wheeled walker as claimed in claim 7,wherein pivoting of the brake lever from the non-braking position to thebraking position moves the brake rod downwardly within the upper andlower frame tubes, bringing the brake device into engagement with thewheel.
 12. A wheeled walker as claimed in claim 7, wherein: pivoting ofthe brake lever from the non-braking position to the braking positionmoves the brake rod upwardly within the upper and lower frame tubes; andthe brake device includes a drawing linkage and a rocker arm which areresponsive to upward movement of the brake rod to bring the brake deviceinto engagement with the wheel.